The invention relates to a noise suppressor unit for installing and mounting a common mode choke for a noise suppressor onto a circuit board, the common mode choke for the noise suppressor comprising a toroid coiled with at least two coils, which coils have two coil ends.
The noise suppressor unit according to the invention can be applied, for example, to installation and mounting of a common mode choke for a noise suppressor in a power source nodule onto a circuit board of the power source module, the module being arranged onto a circuit board of a plug-in unit. A power source module is a separate current delivery device positioned onto a circuit board of a plug-in unit, the device comprising a circuit board for the power source module. Owing to the structure, which comprises two stacked circuit boards, the power source module only allows the use of especially low components in order for the combination to fit into the card slot reserved for it.
Especially the operation of a power source causes much electro-magnetic noise. The European Commission EMC directive (89/336/EEC) on electric devices determines that no device must not be disturbed by other devices nor must it disturb other devices. In the current and future telecommunications community, the fulfilment of the requirements of the directives is of utmost importance, and also constitutes, a competitive advantage. If electromagnetic noise cannot be filtered in the power source module, it propagates and may cause malfunction in the plug-in unit. As a result of this, the operation of the entire system may be disturbed. For this reason, for preventing the propagation of noise, the interface between the power source and the plug-in unit must comprise a noise filter having, among other things, a common mode choke for a noise suppressor of the power source module. The operation of the noise filter is reciprocal.
Common mode chokes for noise suppressors have previously been disposed on the circuit board of a plug-in unit. Common mode chokes for noise suppressors have previously been manually positioned onto the circuit board of the plug-in unit, and the ends of the choke coils have been soldered into openings on the circuit board of the plug-in unit.
When components are assembled onto a circuit board by modem production methods, the above conventional method cannot be used. A common mode choke for a noise suppressor has to be able to be assembled automatically and surface mounted.